Line isolation and address multiplexing system for gas discharge display matrix

ABSTRACT

There is disclosed a line isolation and address multiplexing system for gas discharge display panels wherein gas discharge gates are used. The circuitry including the gas discharge elements for the gates may be discrete components or formed as a part of the display panel.

United States Patent 1 Petty 1451 July 31,1973

1 1 LINE ISOLATION AND ADDRESS MULTIPLEXING SYSTEM FOR GAS DISCHARGE DISPLAY MATRIX [75] Inventor: William D. Ietty, Perrysburg, Ohio [73] Assignee: Owens-Illinois, Inc., Toledo, Ohio [22] Filed: Nov. 3, 1971 [21] Appl. No.1 195,416

[52] US. Cl. 315/169 TV, 315/169 R [51] Int. Cl. 1105b 37/00 [58] Field of Search 307/243; 315/169 R,

[56] References Cited UNITED STATES PATENTS 3,499,167 3/1970 Baker et a1. 315/169 3,513,327 5/1970 Johnson 315/169 TV X 3,183,404 5/1965 Kitz et a1 315/169 R X 2,658,142 11/1953 St. John 328/104 1 Primary Examiner-Roy Lake Assistant ExaminerLawrence J. Dahl Attorney--Dona1d Keith Wedding et a1.

57 ABSTRACT There is disclosed a line isolation and address multiplexing system for gas discharge display panels wherein gas discharge gates are used. The circuitry including the gas discharge elements for the gates may be discrete components or formed as a part of the display panel.

8 Claims, 3 Drawing Figures l K 5%; w W ag LINE ISOLATION AND ADDRESS MULTIPLEXING SYSTEM FOR GAS DISCHARGE DISPLAY MATRIX The present invention is directed to a line isolation and address multiplexing system for gas discharge display panels of the type having inherent memory and, as specifically disclosed in Baker et al. US. Pat. No. 3,499,167 and Bitzer ct al. U.S. Pat. No. 3,559,190. In gas discharge display panels of the type for which the present invention has particular and unique application. discharges, once initiated, are maintained by a sustainer voltage and the presence of a wall voltage due to charges stored on now-conductive walls of the device, which charges and resulting wall voltage constitute an internal memory for such panels. The present invention is directed to circuitry for addressing discrete sites in such panels and employs separate gas discharges as gates and further provides for the elimination of discrete components to achieve line isolation or address multiplexing. The gates are threshold devices so that quarter-select or inadvartent firing of discrete site does not occur.

The above and other objects, advantages and features of the invention will become apparent from the following specification and drawings wherein:

FIG. 1 is a diagrammatical illustration of a panel constructed in accordance with the invention.

FIG. 2 is a schematic circuit representation of the line isolation and address multiplexing circuitry incorporating the invention, and

FIG. 3 is a diagrammatic representation of a discrete discharge site located by any selected row conductor x and any selected column conductor y.

Referring first to circuit diagram of FIG. 2, the column conductor array 12 and the row conductor array 13 are provided with addressing circuits 30 and 31 respectively, such that each column conductor is separately addressable and each row conductor 13 is likewise separately addressable. As shown, a sustainer supply source for the column conductor 12 is provided by sustainer generator 32 which supplies a sustainer voltage V which cooperates with the sustainer voltage for the row conductors 13 from sustainer source 33 which couples a sustainer voltage V Such sustainer generators are well-known in the art and may be the type shown in Murley US. Pat. No. 3,588,597. It will be noted that the sustainer sources 32 and 33 are commonly referenced to a common ground or reference point 34. As shown, a separate gas discharge element 35-1, 35-2, 35-3 35-N is provided to couple the voltage from. sustainer generator 32 to the column conductors 12. In like manner, a separate gas discharge element 36-1, 36-2 36-N is provided to couple the sustainer voltage from source 33 to the row conductors 13. In accordance with this invention. each such discharge gate element 35 and 36 is of the type wherein the electrodes are in direct conductive contact with the gaseous medium. The address circuits 30 and 31 for each column and each row conductor are constituted by a pair of resistors R1 and R2 for the column conductors 12 and a similar pair of resistors R3 and R4 for the row conductors 13. Each resistor R3 and R4 has one terminal commonly connected to the other resistor, respectively, and through a row gas discharge gate element RG (RG-l, RG-2 RG-N to the respective row conductors 13. In like manner, the resistors R1 and R2 are commonly connected together at one end and through column gas discharge gate elements CG (CG-1, CG-Z, CG-N). Furthermore, the row logic resistors R3 and R4 are connected to separate pulsing circuits (not shown) to receive address signals or selection pulses thereon. Finally, the discharge element gates CG-l, CG-N are connected through a resistor R5 from the respective column conductors 12 to a ground or common terminal. Similarly, row selection gate elements RG-l, RG-2 RG-N are each respectively connected through a resistor R6 to a common terminal or ground which is the same as that used for the column conductor resistors. However, this is not necessarily the same ground as ground 34 as they may be different so that the panel 9 floats on the sustainer voltage source with the additional voltages being additively coupled thereto.

The gate elements CG and R6 are simple neon gate elements constructed, preferably but not necessarily, integrally with the panel proper in a manner to be described later herein. However, in operation, these gates CG and RG have a breakdown voltage V, and a sustaining voltage (at which their dynamic resistance is about zero) V The gas in the panel proper has a breakdown voltage V; which is substantially larger than the breakdown voltage V, for the gate elements so that when the sustainer voltage V is applied and the sustainer voltage V is zero, the neon gate elements breakdown first causing V 2V,; to appear across the matrix at any selected cross point. If this value is chosen so that it exists in the bi-stable range of the panel itself, normal operation will result with discharges occuring whenever V is on and V is zero and, vice versa, when V is on and V is equal to zero. In other words, in a normal sustaining state. Whenever both V and V are equal, the gates CG and RG are not fired and the lines are isolated.

If voltages are then applied to the address lines, the applied voltage at will be 2 Vi, where V, is the applied voltage and n is the number of lines (for the example disclosed n=2). That is, the applied address voltage will be the average of these voltages (the average of the voltages applied to the addressing ends of resistors R3, R4, respectively. The values are chosen so that on the selected line the applied voltage (ZVi/n) is much greater than V so that this gate element fires transferring the applied voltage (ZVi/n) minus V to a selected line. On the nonselected lines the applied voltage (EVi/n) is very much less than V so that no voltage appears on these lines. In a similar manner an electrode of the opposite or orthogonal array may be selected so that the cell designated by their intersections is selected and addressed, e.g., the matrix crosspoint selected and addressed (see FIG. 3).

In FIG. 2 the various resistor and discharge elements forming each logic or gate element for line addressing is shown as discrete components. However, in a preferred embodiment of the invention as shown in FIG. 1, no discrete components are necessary to achieve the line isolation and address multiplexing. In the embodiment shown in FIG. 1, the discrete resistor elements are formedby way of thick film resistors. Thus, the resistors R6'for the row conductor addressing are formed as a single deposition of thick film resistor material R6TF on plate 10.A common conductor or ground bus 50 is deposited upon this material and extended to the edge of the panel for connection to external circuitry. In a like manner, the individual resistors R5 are formed by a single deposition of film resistor material RS-TF on the ends of the column conductors 12 and a single ground bus 51 is applied overthis resistance material to form all these resistors in the connection shown in FIG. 2. Resistors R3 and R4 are formed by depositing conductor discharge gate leads to a common electrode point 70 with the thick film resistor material forming resistors R3 and R4 applied in the pattern shown with the conductor address lines leading to the edge of the plate being solid conductor material with the resistance material in between these two address lines and gate electrode point 70. The same technique is used in connection with row conductor plate 11 to form the addressing resistors R3 and R4. The electrode point 70 forms one electrode of a gas discharge device or gate element much in the same fashion as a simple neon discharge tube. Its cooperating conductor or electrode is the opposite heavy conductor extensions 75-1, 75-2 75-N of the respective row and column conductor arrays. The neon discharge devices 36-1, 36-2 36N for coupling the sustainer voltage to the row conductor array 13 is formed by depositing a single broad conductive element 80 which is spaced from and opposite the terminals75-I, 75-2, 75-N with the N or lead line 82 thereof extended to the edge of the plate for connection to the sustainer supply 33. (This connection is designated 82' in FIG. 2). The dielectric layers 14 and 15 on the column and row conductor arrays 12 and 13 respectively, may have a spacer sealant 16 applied much in the same manner as is disclosed in the aforementioned Baker et al. patent and the device filled with an operating gas by means of a gas filling tubulation not shown. The gas may be a mixture of 99.9 percent neon and about 0.1 percent argon at a pressure of about 600 torr. In addition, the gas diodes or discharge devices RG-l RG-N and CG-l CG-N as well as the sustainer coupling discharge elements 36-1 36-N and 35-1 35-N may be provided with a separate operating gas, such as a gas at low pressure, by sealing the entire device in a further external envelope. However, the second gas in this case may be provided by simply forming two gas chambers, the first of which is defined by the boundaries of the viewing area of the device e.g., by spacer sealant l6 and the second of which is defined by the external perimeter spacer sealant 18 for the operating circuitry described herein. A separate gas filling tubulation (not shown) may be used.

The device provides a direct current discharge gating system whereby no discrete components are necessary to achieve line isolation or address multiplexing. Moreover, each gate acts as a threshold linear adder so that spurious pulsing of individual units does not occur.

While preferred embodiments of the invention have been disclosed, it is clear that various modifications and changes obvious to those skilled in the art may be made without departing from the spirit of the invention as defined in the following claims.

I claim:

1. In a gas discharge panel device of the type having a pair of glass plates, spacer sealant means joining said plates in spaced relation and a transverse angle to each other to form a thin gas chamber, and linear rowcolumn conductor arrays on said plates defining a cross conductor matrix, dielectric material on said arrays, and a source of electrical operating potentials for said row and said column conductors, respectively, including a continuously applied periodic sustaining voltage and discharge condition manipulating pulse potential improvements in a selected and addressing circuitry for selecting individual one of said conductors for application thereto of said pulse potentials, the improvements comprising a first gas discharge device individual to each conductor in each array for coupling discharge condition manipulating potentials thereto, each said gas discharge device having a pair of electrodes in direct conductive contact with a gas medium.

2. The invention defined in claim 1 wherein each conductor in said panel includes a further gas discharge device for coupling thereto said sustaining voltage.

3. The invention defined in claim 1, including resistor means for coupling said discharge condition manipulating pulse potentials to the said first gas discharge device.

4. The invention defined in claim 3, wherein each said resistor element is formed as an integral part of said panel.

5. The invention claimed in claim 1 wherein said first gas discharge device is formed as an integral part of said panel.

6. The invention defined in claim 1 wherein each said first gas discharge device being a two electrode discharge element and included in a gate circuit, said gate circuit further including,

at least a pair of resistor elements having a pair of common ends connected to one electrode of said direct current discharge device and each respective opposite end connected to sources of operating potentials, respectively,

and a third resistor connected at one end to the other electrode of said direct current discharge device and the one said individual conductor in said array and at the other end to a point common to all such resistors on that set of conductors.

7. The invention defined in claim 6 wherein all the components of said gate circuit are formed as integral parts of said panel.

8. The invention defined in claim 1 wherein said first gas discharge device has a breakdown voltage which is great enough to prevent below a selected level from causing a discharge therein.

* l i i 

1. In a gas discharge panel device of the type having a pair of glass plates, spacer sealant means joining said plates in spaced relation and a transverse angle to each other to form a thin gas chamber, and linear row-column conductor arrays on said plates defining a cross conductor matrix, dielectric material on said arrays, and a source of electrical operating potentials for said row and said column conductors, respectively, including a continuously applied periodic sustaining voltage and discharge condition manipulating pulse potential improvements in a selected and addressing circuitry for selecting individual one of said conductors for application thereto of said pulse potentials, the improvements comprising A first gas discharge device individual to each conductor in each array for coupling discharge condition manipulating potentials thereto, each said gas discharge device having a pair of electrodes in direct conductive contact with a gas medium.
 2. The invention defined in claim 1 wherein each conductor in said panel includes a further gas discharge device for coupling thereto said sustaining voltage.
 3. The invention defined in claim 1, including resistor means for coupling said discharge condition manipulating pulse potentials to the said first gas discharge device.
 4. The invention defined in claim 3, wherein each said resistor element is formed as an integral part of said panel.
 5. The invention claimed in claim 1 wherein said first gas discharge device is formed as an integral part of said panel.
 6. The invention defined in claim 1 wherein each said first gas discharge device being a two electrode discharge element and included in a gate circuit, said gate circuit further including, at least a pair of resistor elements having a pair of common ends connected to one electrode of said direct current discharge device and each respective opposite end connected to sources of operating potentials, respectively, and a third resistor connected at one end to the other electrode of said direct current discharge device and the one said individual conductor in said array and at the other end to a point common to all such resistors on that set of conductors.
 7. The invention defined in claim 6 wherein all the components of said gate circuit are formed as integral parts of said panel.
 8. The invention defined in claim 1 wherein said first gas discharge device has a breakdown voltage which is great enough to prevent below a selected level from causing a discharge therein. 